An important parameter in optical communications systems is the coupling efficiency of light emitted by a light emitting device, such as a semiconductor light emitting diode or laser, into an optical fiber. Efficient coupling of light into the fiber occurs when an end of the fiber is brought very close to and aligned with the emitting portion of the facet of the light emitting device. To improve the efficiency of the coupling, an optical coupling medium such as a refractive index matching material which may also be a cement, is inserted between the end of the fiber and the emitting facet. Such an index matching material reduces reflections at the facet-air and air-fiber interfaces, thereby increasing the amount of light coupled into the fiber and reducing the intensity of spurious reflected beams which may be coupled into the fiber. Cementing the fiber to the facet also maintains the alignment of the fiber and the emitting facet thereby improving the reliability of the assembly. At the present time assemblies of light emitting devices and optical fibers perform with adequate efficiency. However, further improvements in the efficiency of the coupling of light into an optical fiber are clearly desirable to improve the overall system performance.